Rogers, ranked 113rd in the world, took advantage of six double faults by a mistake-prone Bouchard to hand the fifth-seeded Montreal native a 6-0, 2-6, 6-0 defeat on the hardcourts at Uniprix Stadium.

Bouchard was competing in her first tournament since reaching her first career Grand Slam final at Wimbledon last month, where she was beaten by Petra Kvitova in straight sets.

Third seed Agnieszka Radwanska had an easier time in her second-round match with Barbora Zahlavova Strycova, with the Polish star getting past the rising Czech 6-4, 6-4. Eighth-seeded Victoria Azarenka also advanced to the third round via a hard-fought 6-4, 2-6, 6-4 decision over France's Alize Cornet.

This week's top seeds are U.S. Open and reigning Rogers Cup champion Serena Williams, Wimbledon winner Kvitova, Radwanska and French Open champ Maria Sharapova. Serena Williams, last week's Stanford titlist, will open her Montreal stay against Stosur, who stunned the American in the 2011 U.S. Open final. Kvitova will face Dellacqua in the round of 32.